More than three million people in Britain are now vapers, new data has revealed.

Action on Smoking and Health found there are now four times more e-cigarette users than there was six years ago.

The charity today said smokers are ‘finally getting the message’ that switching to vaping can improve health.

Vaping – the term for using e-cigs – is less harmful than conventional smoking, known to directly cause cancer and heart disease.

But the gadgets have been subject to huge controversy recently, due to worrying links between heart and lung damage and vaping.

Vaping – the term for using e-cigs – is less harmful than conventional smoking, known to directly cause cancer and heart disease

E-cigarettes contain a liquid form of nicotine that is heated into vapour to be inhaled, avoiding the harm caused by tobacco smoke.

ASH first started conducting surveys of thousands of adults to estimate the number of vapers in Britain back in 2012.

In its first year of collecting answers, it claimed there were approximately 700,000 e-cigarette users across the home nations.

This figure almost doubled by the next year and has slowly crept up every 12 months. However, it has plateaued since 2015.

ASH estimates there are around 3.2 million vapers in Britain in 2018 – in the region of six per cent of the total population.

It is also 10 per cent up on the amount estimated for 2017, according to the poll of the smoking habits of 12,000 adults.

Most revealed they have turned to vaping because they have quit smoking and 40 per cent are smokers who are trying to give up.

Public Health England claim vaping is around 95 per cent less harmful than smoking conventional tobacco cigarettes.

The Government-run body said in February that the gadgets should be made available on prescription for smokers wanting to quit.

And a lengthy report by MPs last month said strict rules around e-cigarettes should be relaxed to let users vape on public transport.

However, another official body, the watchdog Nice, has previously told GPs not to recommend e-cigarettes because there is limited evidence over their safety.

And the international scientific community is divided over e-cigarettes as a nicotine replacement therapy amid an array of worrying studies.

Just last month Birmingham University research suggested vaping triggers the production of damaging inflammatory chemicals in the airways.

Deborah Arnott, chief executive of ASH, said: ‘UK policy is on the right track with thousands of smokers making the switch to vaping and improving their health and little sign of non-smokers taking up vaping.

‘But even more smokers could benefit if e-cigarettes were licenced as medicines and available on prescription.’

Dr Leonie Brose, of King’s College London, added: ‘The continued false belief among some smokers that vaping is as bad as smoking is worrying.

‘Campaigns from Public Health England and others to challenge these views are important and must continue.’

What is an e-cigarette and how is it different to smoking tobacco?

An electronic cigarette (e-cigarette) is a device that allows users to inhale nicotine by heating a vapour from a solution that contain nicotine, propylene and flavourings.

As there is no burning involved, there is no smoke like a traditional cigarette.

But while they have been branded as carrying a lower risk than cigarettes, an increasing swell of studies is showing health dangers.

E-cigarettes do not produce tar or carbon monoxide, but the vapor does contain some harmful chemicals.

Nicotine is the highly addictive chemical which makes it difficult for smokers to quit.

Nearly three million people in Britain use e-cigarettes, and more than nine million Americans.

TYPES:

1. Standard e-cigarette

Battery-powered device containing nicotine e-liquid.

It vaporizes flavored nicotine liquid.

2. Juul

Very similar to normal e-cigarettes but with sleeker design and a higher concentration of nicotine.

Thanks to its ‘nicotine salts’, manufacturers claim one pod delivers the amount of nicotine as a pack of cigarettes.

It is composed of an e-cigarette (battery and temperature control), and a pod of e-liquid which is inserted at the end.

The liquid contains nicotine, chemicals and flavorings.

Like other vaping devices, it vaporizes the e-liquid.

3. IQOS by Philip Morris

Pen-shaped, charged like an iPod.

Vaporizes tobacco.

It is known as a ‘heat not burn’ smokeless device, heating tobacco but not burning it (at 350C compared to 600C as normal cigarettes do).

The company claims this method lowers users’ exposure to carcinogen from burning tobacco.